Disk drives are manufactured in clean rooms in order to prevent damage to the disk drives from particles getting inside of the disk drives. Disk drives are also subject to being damaged from electrostatic discharge (ESD), which is the discharge of electrostatic charge between components that have different potentials, during the manufacturing process. In order to minimize the possibility of ESD, the relative humidity inside of a clean room is typically maintained at approximately 55 percent.
However, it is desirable that the relative humidity inside of a disk drive after it has been manufactured is approximately 25 percent to 30 percent in order to avoid the failure of disk drive components, such as the magnetic read write heads, due to corrosion of the components. Desiccants are typically placed inside of disk drives in order to maintain a relative humidity of approximately 25 percent to 30 percent inside of the disk drive. However, since the clean room typically has a relative humidity of approximately 55 percent much of the life span of the desiccant is used up while the disk drive is being manufactured. Thus, the life of the disk drive is shortened.
FIG. 1 depicts a plan view of a prior art disk drive in order to facilitate the discussion of using desiccants inside of disk drives. The disk drive 110 includes a base casting 113, a motor hub assembly 130, a disk 112, actuator shaft 132, actuator arm 134, suspension assembly 137, a hub 140, voice coil motor 150, a magnetic read write head 156, a slider 155, and desiccant 160.
The components are assembled into a base casting 113, which provides attachment and registration points for components and sub assemblies. A plurality of suspension assemblies 137 (one shown) can be attached to the actuator arms 134 (one shown) in the form of a comb. A plurality of transducer heads or sliders 155 (one shown) can be attached respectively to the suspension assemblies 137. Sliders 155 are located proximate to the disk 112's surface 135 for reading and writing data with magnetic heads 156 (one shown). The rotary voice coil motor 150 rotates actuator arms 135 about the actuator shaft 132 in order to move the suspension assemblies 150 to the desired radial position on a disk 112. The desiccant 160 is typically placed near the voice coil motor 150. The actuator shaft 132, hub 140, actuator arms 134, and voice coil motor 150 may be referred to collectively as a rotary actuator assembly.
Data is recorded onto disk surfaces 135 in a pattern of concentric rings known as data tracks 136. Disk surface 135 is spun at high speed by means of a motor-hub assembly 130. Data tracks 136 are recorded onto spinning disk surfaces 135 by means of magnetic heads 156, which typically reside at the end of sliders 155.
FIG. 1 being a plan view shows only one head, slider and disk surface combination. One skilled in the art understands that what is described for one head-disk combination applies to multiple head-disk combinations, such as disk stacks (not shown). However, for purposes of brevity and clarity, FIG. 1 only shows on head and one disk surface.